To find the answer to "What two numbers have a product of 90 and a sum of 49?" we first state what we know. We are looking for x and y and we know that x • y = 90 and x + y = 49.
Before we keep going, it is important to know that x • y is the same as y • x and x + y is the same as y + x. The two variables are interchangeable. Which means that when we create one equation to solve the problem, we will have two answers.
To solve the problem, we take x + y = 49 and solve it for y to get y = 49 - x. Then, we replace y in x • y = 90 with 49 - x to get this:
x • (49 - x) = 90
Like we said above, the x and y are interchangeable, therefore the x in the equation above could also be y. The bottom line is that when we solved the equation we got two answers which are the two numbers that have a product of 90 and a sum of 49. The numbers are:
1.91129
47.08871
That's it! The two numbers that have a product of 90 and a sum of 49 are 1.91129 and 47.08871 as proven below:
1.91129 • 47.08871 ≈ 90
1.91129 + 47.08871 = 49
Note: Answers are rounded up to the nearest five decimals if necessary so the answers may not be exact.
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